Method and device for heat treatment

ABSTRACT

After carrying an LCD substrate in a reaction container of a heat treatment unit, blowing a previously heated helium gas from a gas supply part, which opposes to the surface of the LCD substrate, over the entire surface of the LCD substrate. The temperature of the LCD substrate is raised by radiation heat of a heater and heat exchange with the helium gas. After performing CVD or annealing in the reaction container, cooling the LCD substrate by blowing a gas for heat exchange having a temperature about a room temperature from the gas supply part over the entire surface of the LCD substrate. Return the cooled LCD substrate to a carrier in the carrier chamber via a conveyance chamber.

TECHNICAL FIELD

[0001] The present invention relates to heat treatment method and heattreatment apparatus and, more particularly, to a heat treatment methodand a heat treatment apparatus which are used for manufacturingsemiconductors.

BACKGROUND ART

[0002] A liquid crystal panel is used as a display of computers ortelevisions. A glass substrate for liquid crystal displays (hereinafter,referred to as an LCD substrate) has been enlarged increasingly inrecent years. Various semiconductor manufacturing processes areperformed for forming devices such as a thin film transistor (TFT) onthe LCD substrate. Among such processes, a heat treatment process isperformed by a single-wafer type cold-wall heat treatment apparatus,which processes substrates one by one. This apparatus heats a substratecarried in a chamber from above by a heating lamp. As for a large-sizeLCD substrate, since heat radiation from a circumferential edge islarge, it is preferable to use a hot-wall type heat treatment apparatuswhich heats a substrate while heating walls of a reaction container by aheater surrounding the reaction container.

[0003] Meanwhile, recently, in order to achieve a higher throughput, asystem referred to as a cluster tool is used, which is constituted byconnecting airtightly a carrier chamber, which performs carry-in andcarry-out of a substrate carrier, to a conveyance chamber in which aconvey arm is installed and further connecting airtightly a plurality ofheat treatment chambers to the conveyance chamber.

[0004] The hot-wall type heat treatment apparatus requires a long timefor heating and cooling a substrate. For example, when a substrate isattracted onto a placement stage by an electrostatic chuck as in acold-wall type heat treatment apparatus, a rapid heat exchange can beperformed between the substrate and the placement stage by supplying aheating medium to an extremely small gap between the backside of thesubstrate and the placement stage. However, since the electrostaticchuck cannot be used in the hot-wall type, a large gap is presentbetween a substrate and a placement stage. For this reason, if anattempt is made to take measures of a cold-wall type, especially in acase of a large-size LCD substrate, it is difficult to cool downuniformly and rapidly. Therefore, when an attempt is made to incorporatea hot-wall type heat treatment apparatus which performs a heat treatmentof an LCD substrate, it takes a long time to heat and cool the substrateby the heat treatment apparatus, and, thus, there is a problem in that afunction of a high throughput which is provided by a cluster tool cannotbe sufficiently used.

DISCLOSURE OF INVENTION

[0005] It is a general object of the present invention to provide animproved and useful heat treatment apparatus and heat treatment methodin which the above-mentioned problems are eliminated.

[0006] A more specific object of the present invention is to provide aheat treatment apparatus and method which can achieve a high throughputwhen applying a heat treatment to a glass substrate.

[0007] In order to achieve the above-mentioned objects, there isprovided according to one aspect of the present invention a heattreatment method of performing a heat treatment using a heat treatmentapparatus constituted by connecting airtightly a carrier chamber which asubstrate is carried in and carried out, a conveyance chamber forconveying the substrate and a hot-wall type heat treatment unit forheat-treating the substrate, a glass substrate for liquid crystaldisplays being taken from a substrate carrier in the carrier chamber byconveying means in said conveyance chamber and being conveyed into saidheat treatment unit in which a heat treatment is applied to the glasssubstrate, the method comprising: a step of conveying the glasssubstrate from said conveyance chamber into a reaction container insidesaid heat treatment unit; a step of heating an interior of said reactioncontainer at a process temperature so as to apply a heat treatment tothe glass substrate; a step of supplying a gas for heat exchange to asurface of said glass substrate so as to perform heat exchange betweensaid glass substrate and the gas in at least one of a step of raising atemperature inside said reaction container to the process temperatureand a step of decreasing the temperature of the reaction container afterthe heat treatment; and a step of carrying the heat treated glasssubstrate out of said reaction container.

[0008] In the above-mentioned present invention, the gas for heatexchange is preferably blown from a gas supply part opposite to thesurface of the glass substrate to substantially the entire surface ofthe glass substrate. Additionally, the gas for heat exchange ispreferably adjusted previously to a predetermined temperature beforebeing supplied to inside said reaction container. Specifically, forexample, a first gas for heat exchange is supplied to the glasssubstrate in a step of raising the temperature inside said reactioncontainer to a process temperature, and a second gas for heat exchange,which has a temperature lower than the temperature of said first gas forheat exchange, is supplied to said glass substrate in a step ofdecreasing the temperature inside said reaction container after the heattreatment.

[0009] Additionally, during a step of raising the temperature inside thereaction container to the process temperature, at least one ofincreasing an amount of the gas for heat exchange and raising atemperature of the gas for heat exchange before being supplied to thereaction container may be performed. Further, during a step ofdecreasing the temperature inside the reaction container to the processtemperature, at least one of increasing an amount of the gas for heatexchange and decreasing a temperature of the gas for heat exchangebefore being supplied to the reaction container may be performed.

[0010] Further, the heat treatment method according to theabove-mentioned present invention may includes a step of dividing theglass substrate placed in said reaction container into a plurality ofareas and supplying independently a gas for heat exchange to each of theareas; a step of detecting a temperature of each of the divided areas ofsaid glass substrate; and a step of controlling at least one of anamount of flow and a temperature of the gas for heat exchange to besupplied to each divided area. Thereby, heating and cooling of the glasssubstrate can be performed with a further higher in-plane uniformity.

[0011] Additionally, there is provided according to another aspect ofthe present invention a heat treatment apparatus constituted byconnecting airtightly a carrier chamber which a substrate is carried inand carried out, a conveyance chamber for conveying the substrate and ahot-wall type heat treatment unit for heat-treating the substrate, aglass substrate for liquid crystal displays being taken from a substratecarrier in the carrier chamber by conveying means in said conveyancechamber and being conveyed into said heat treatment unit in which a heattreatment is applied to the glass substrate, comprising: a placementpart for placing the glass substrate in said reaction container; a gassupply part for supplying a gas for heat exchange to a surface of theglass substrate placed on the placement part; a flow passage opening andclosing part provided to a gas flow path for delivering the gas to saidgas supply part; a control part controlling the flow passage opening andclosing part so as to supply a gas for heat exchange to said glasssubstrate in at least one of a step of raising a temperature inside saidreaction container to the process temperature and a step of decreasingthe temperature of the reaction container after the heat treatment.

[0012] Other objects, features and advantages of the present inventionwill become more apparent from the following detailed description whenread in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is an illustrative plan view showing an entire heattreatment apparatus according to a first embodiment of the presentinvention.

[0014]FIG. 2 is a cross-sectional view of a hot-wall type heat treatmentunit used in the heat treatment apparatus shown in FIG. 1.

[0015]FIG. 3 is a flow chart of a process performed by the heattreatment apparatus shown in FIG. 1.

[0016]FIG. 4 is a structural diagram of a heat treatment apparatusaccording to a second embodiment of the present invention.

[0017]FIG. 5 is a perspective view of a gas supply part and an LCDsubstrate use in the heat treatment apparatus shown in FIG. 4.

[0018]FIG. 6 is a structural diagram showing a part of a heat treatmentapparatus according to a third embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENITON

[0019] A description will be given below, with reference to thedrawings, of embodiments according to the present invention. It shouldbe noted that the same parts in the drawings are give the same referencenumbers.

[0020]FIG. 1 is a plan view showing an outline structure of a heattreatment apparatus according to a first embodiment of the presentinvention. The heat treatment apparatus shown in FIG. 1 comprises acarrier chamber 1, a conveyance chamber 2, and a plurality of hot-walltype heat treatment units 3 (two units in the figure). The carrierchamber 1 and the conveyance chamber 2 are airtightly connected througha gate valve G1. Additionally, the conveyance chamber 1 and the heattreatment units 3 are connected through a gate valve G2, respectively.

[0021] The carrier chamber 1 is an airtight chamber for carrying in andout a carrier C, which is a convey tool for conveying a plurality ofrectangular LCD substrates by retaining in a shelf-like state, betweenoutside of the apparatus through a gate door G3. The conveyance chamber2 provides a convey means 21 which comprises a multi-joint arm. Theconvey means 21 is constituted so that the LCD substrates 10 can bedelivered between the carrier C in the carrier chamber 1 and so that theLCD substrates 10 can be delivered between the below-mentioned placementpart of the heat treatment unit 3. The carrier chamber 1 and theconveyance chamber 2 are equipped with a gas supply and exhaust systemwhich is not illustrated, and the inside thereof is made to be aninactive gas atmosphere.

[0022] As shown in FIG. 2, in order to form a heat treatment atmosphere,the heat treatment unit 3 comprises: a quartz-made cylindrical reactioncontainer 4 having an open bottom; a cylindrical insulator having anopen bottom side and provided so as to surround the reaction container4; a heater 32 which is provided on an inner surface and an outersurface of the insulator 31 and constitutes a furnace body together withthe insulator 31; a transfer camber 33 located on the bottom side of thereaction container 4 and surrounded by a housing 30; and a placementpart 41 which holds the LCD substrates 10 at four points, for example,near the outer edge and moves up and down between the transfer chamber33.

[0023] The placement part 41 is provided on a cap 42, which opens andcloses a lower end opening part of the reaction container 4 through asupport rod 43. The cap 42 is provided on an upper part of anup-and-down axis 44, and is moved up and down by an up-and-downmechanism 45 on the lower side of the transfer chamber 33. A conveyanceopening 33 a is formed on a sidewall of the transfer chamber 33 so thatan arm of the convey means 21 shown in FIG. 1 can transfer the LCDsubstrates 10 between the placement part 41. The transfer chamber 33 isequipped with a gas supply and exhaust system which is not illustrated,and can form an inactive gas atmosphere. Moreover, although notillustrated, a cap which is slidable and movable up and down is providedin an upper part of the transfer chamber 33 so as to close the lower endopening of the reaction container 4 when the placement part 41 islocated in the transfer chamber 33.

[0024] A gas-supply part 5 is provided on the upper part side of thereaction container 4, and an exhaust pipe 46 is connected to a lowerpart side. First, a description will be given of the exhaust pipe 46.The exhaust pipe 46 is constituted so that an exhaust can be performedby switching between a vacuum exhaust means not shown in the figure andan exhaust pump. For this reason, both a vacuum atmosphere and anormal-pressure atmosphere can be formed while evacuating the inside ofthe reaction container 4.

[0025] The gas-supply part 5 has many gas-ejecting holes 51 on a lowersurface of a flat cylindrical part connecting the reaction container 4so as to make an area opposite to an entire surface of the LCD substrateto be a gas-blowing area. A gas-supply pipe 52, which forms a gas-supplypassage, is connected to the upper surface side of the gas-supply part5. The gas supply pipe 52 is branched into a gas-supply pipe 53 forsupplying a process gas and a gas-supply pipe 54 for supplying a gas forheat exchange.

[0026] The gas-supply pipe 53 is connected to a process gas supplysource, which is not illustrated in the figure, through a valve VC,which is a flow-passage opening-and-closing part. The gas-supply pipe 54is branched into a first gas-supply pipe 55 for supplying a first heatexchange gas (gas for heating) when heating the LCD substrate 10 and asecond gas-supply pipe 56 for supplying a first heat exchange gas (gasfor cooling) when cooling the LCD substrate 10. The first gas-supplypipe 55 is provided with a gas-supply source 61 of the first heatexchange gas, a supply source of, for example, a helium gas which is aninert gas, a temperature-control part 62 containing a heating part foradjusting the helium gas to a first temperature, a gas flow adjustmentpart 63 which consists of, for example, a mass flow meter and a valve 64which is a flow-passage opening-and-closing part, in that order from anupstream side. Additionally, the second gas-supply pipe 56 is providedwith a gas-supply source 71 of the second heat exchange gas, a supplysource of, for example, a helium gas which is an inert gas, atemperature-control part 72 for adjusting the helium gas to a secondtemperature which is lower than said First temperature, a gas flowadjustment part 73 which consists of, for example, a mass flow meter anda valve 74 which is a flow-passage opening-and-closing part, in thatorder from an upstream side.

[0027] The first temperature, which is an adjustment temperature of thefirst heat exchange gas, is a temperature slightly lower than thetemperature (process temperature) of the heat treatment atmosphere whenperforming a heat treatment. The second temperature, which is anadjustment temperature of the second heat exchange gas may be a roomtemperature, or may be a temperature between the room temperature andthe process temperature. Although the temperature-control part 72 isprovided with a heating part when setting the second temperature to atemperature higher than a room temperature, the temperature control part72 is provided with a cooling part when setting the second temperatureto a temperature lower than a room temperature.

[0028] It should be noted that, when setting the second temperature to aroom temperature, it is not necessary to provide the temperature-controlpart 72. In this example, although the gas-supply pipe 55 of the firstheat exchange gas and the gas-supply pipe 56 of the second heat exchangegas are separated, these gas-supply pipes 55 and 56 may be made commonso as to commonly use the temperature-control part. In such a case, thetemperature setting may be changed when supplying the first heatexchange gas and when supplying the second heat exchange gas.

[0029] The heat treatment apparatus is provided with a control part 100as shown in FIG. 2. The control part 100 outputs signals for controllingvalves 50, 64 and 74 so as to control supply and stop of a process gasand a heat exchange gas supplied to the reaction container 4.Additionally, the control part 100 has a series of sequence programs soas to perform a temperature control and a flow control of the first andsecond gases by outputting control signals for the temperature-controlparts 62 and 72 and flow adjustment parts 63 and 73.

[0030] Next, a description will be given, with reference to theflowchart of FIG. 3, of a process in the above-mentioned embodiment.First, a carrier C, which retains a plurality of sheets of LCDsubstrates 10, is carried in from outside a carrier chamber 1 which ismade into an inert gas atmosphere by being always supplied with, forexample, an inert gas (step S1). After closing the gate door G3, gatevalve G2 is opened so as to transfer the LCD substrate 10 to a placementpart 41 in the transfer chamber 33 of one of the heat treatment units 3,and the LCD substrate 10 is carried in the reaction container 4 by theup-and-down mechanism 45 (step S2). The conveyance chamber 2 and thetransfer chamber 33 are also made into an inert-gas atmosphere, and,therefore, the LCD substrate is transferred within the inert-gasatmosphere. Moreover, although the heater 32 is turned off, for example,when the LCD substrate 10 is carried in the reaction container 4, thetemperature is higher than a room temperature since the heat by the heattreatment of the LCD substrate 10 remains.

[0031] When the placement part 41 moves up to an upper limit location, alower-end opening of the reaction container 4 is closed by the cap 42.Thereafter, the valve 64 is opened so as to supply a first heat exchangegas, for example, a helium gas to an entire surface of the LCD substratethrough the gas-ejecting holes 51 of the gas-supply part 5, the firstheat exchange gas being heated by the temperature control part 62 to atemperature slightly lower than the process temperature of the heattreatment which will be performed from now. Additionally, the heater 32is turned on to increase a power so as to heat the interior of thereaction container 4. Consequently, the temperature of the LCD substrate10 rapid increases due to the radiation heat from the heater 32 and theconduction of heat from the hot helium gas. Then, the helium gas is alsoheated toward the process temperature as the calorific power of theheater 32 increases. Therefore, the temperature of the LCD substrate 10uniformly increases up to the process temperature by the heat exchangewith the helium gas (step S3). At this time, the inside of the reactioncontainer 4 is, for example, in a normal pressure state, and isevacuated by an exhaust pump which is not illustrated through theexhaust pipe 46.

[0032] Then, the valve 64 is closed and evacuation of the inside of thereaction container 4 is carried out to a predetermined degree of vacuumby the evacuation means, which is not illustrated and connected to theexhaust pipe 46 and which are not illustrated. Thereafter, the valve 64is closed and the valve 50 is opened to supply, for example, a processgas for CVD to inside the reaction container 4 so as to form a thin filmon the LCD substrate 10 (step S4). It should be noted that the timingfor evacuation may be before the LCD substrate 10 reaches the processtemperature. After completion of the CVD process, an annealing processis performed subsequently. When the process temperature of the annealingprocess is higher than the process temperature of the CVD process, aheat exchange may be performed with LCD substrate 10, in addition to theheating by the heater 32, by supplying to the reaction container 4 ahelium gas of which temperature is adjusted to a temperature higher thanthe process temperature of the CVD process, for example, by thetemperature control part 62.

[0033] The annealing process is performed while supplying the processgas for anneal to the reaction container 4 in a depressurized-state of,for example, a viscous-flow range (step S5). After the annealing processis completed, the heater 32 is turned off, the valve 50 is closed andthe valve 74 is opened so as to supply a helium gas, which is a secondheat exchange gas, from the gas-supply part 5 to the reaction container4. The helium gas is ejected over the entire surface of the LCDsubstrate 10 from the gas-ejecting holes 51 after being adjusted by thetemperature control part 72 to a temperature (carrier carry-in allowabletemperature) which does not give influence even if, for example, the LCDsubstrate 10 is carried to the carrier C. For this reason, the heat ofthe LCD substrate 10 is taken by the helium gas, and the LCD substrateis cooled quickly and uniformly (step S6). At this time, the inside ofthe reaction container 4 is, for example, in the normal-pressure state,and is evacuated by the exhaust pump, which is not illustrated, throughthe exhaust pipe 46. It should be noted that the carrier carry-inallowable temperature is a temperature lower than 200 degrees.

[0034] After the LCD substrate 10 is cooled, the placement part 41 ismoved down to the transfer chamber 33, and the LCD substrate 10 on theplacement part 41 is conveyed to the original carrier C in the carrierchamber 1 by the conveyance means 21 (refer to FIG. 1) (step S7).Additionally, when the installation part 41 is moved down, the lower-endopening of the reaction container 4 is closed by the previouslymentioned cap which is not illustrated. After all of the LCD substrates10 in the carrier C are processed, the gate door G3 is opened and thecarrier C is carried outside (step S8).

[0035] In the above-mentioned, as for an example of the consecutiveprocess of CVD and annealing processes, there is an example in which anature of a metal oxide film is changed within an oxygen gas atmosphereafter producing the metal oxide film by CVD.

[0036] According to the above-mentioned embodiment, after the LCDsubstrate 10 is carried in the reaction container 4, the heated heatexchange gas is supplied over the entire surface of the LCD substrate 10so as to raise the temperature of the LCD substrate by utilizing heatexchange with the gas in addition to the radiation heat from the heater32, and, thereby, the LCD substrate 10 can be uniformly and rapidlyheated over the entire surface thereof. Additionally, after the heattreatment, the low temperature heat exchange gas is supplied over theentire surface of the LCD substrate 10 so as to cool the LCD substrate10 by utilizing heat exchange with the gas, and, thereby, the entiresurface of the LCD substrate 10 can be cooled uniformly and rapidly tothe carrier carry-in allowable temperature so that the LCD substrate canbe immediately returned to the carrier C. Although it is more difficultto increase and decrease a temperature uniformly as the LCD substratebecomes larger, the temperature of the LCD 10 can be uniformly andrapidly increased and decreased according to the method of the presentembodiment. Additionally, a high throughput is obtained while being ableto suppress a thermal stress and being able to prevent a crack of aglass substrate or a damage of a device.

[0037] In the above-mentioned example, although CVD and anneal areperformed in the same heat-treatment unit 3, those heat treatments maybe performed in separate heat treatment units 3. Moreover, as for theconsecutive process, there is a process in which an oxidation processfor oxidizing a silicon film is performed and thereafter the oxidationfilm is annealed in a nitrogen gas atmosphere so as to nitride thesurface thereof. It should be noted that the present invention isapplicable to a case where a heat treatment such as a CVD, an oxidationprocess or a diffusion process is performed without performing aconsecutive process.

[0038] Next, a description will be given, with reference to FIG. 4 andFIG. 5, of a second embodiment of the present invention. In the secondembodiment of the present invention, the LCD substrate 10 on theplacement part 41 is divided into a plurality of areas, that is, forexample, two parts including a square shape center-section area S1 andan outside area S2 surrounding the center-section area S1 so that thefirst or second heat exchange gas can be supplied to the LCD substrate10 independently for each divided area (the center-section area S1,outside area S2). Specifically, the gas-supply part 5 is divided by apartition wall 80 into a center-section partition chamber 81, whichcorresponds to the square center-section area S1, and an outsidepartition chamber 82 on an outer side. Additionally, each of the gassupply pipe 55 for the first heat exchange gas and the gas-supply pipe56 for the second heat exchange gas is divided into two systemsincluding a system for supplying a gas to the center-section partitionchamber 81 and a system for supplying a gas to the outside partitionchamber 82. The gas supply pipes indicated by the reference signs 55-1and 55-2 in FIG. 4 are for supplying the first heat exchange gas whenheating the LCD substrate, and are connected to the center-sectionpartition chamber 81 and the outside partition chamber 82 throughgas-supply pipes 99 and 92, respectively. Additionally, the gas-supplypipes indicated by the reference signs 56-1 and 56-2 are connected tothe center-section partition chamber 81 and the outside partitionchamber 82 through the gas-supply pipes 99 and 92, respectively so as tosupply the second heat exchange gas when cooling the LCD substrate.63-1, 63-2, 73-1, and 73-2 are flow control parts, and 64-1, 64-2, 74-1,and 74-2 are valves.

[0039] Moreover, the placement part 41 is provided with atemperature-detecting part 111 which detects a temperature of thecenter-section area S1 of the LCD substrate 10 and atemperature-detecting elements 112 and 113 which detect temperatures ofthe outside area S2 of the LCD substrate 10. For example, a thermocoupleis used for these temperature-detecting parts. The control part 100takes the temperature detection results by these temperaturedetecting-parts 111-113, and sends control signals to the flow controlparts (64-1, 64-2, 74-1, 74-2) so as to adjust, for example, a flow ofthe first or second heat exchange gas so that uniformity in thetemperature in the surface of the LCD substrate is improved inaccordance with the results.

[0040] AS for the method for processing the detected values of thetemperature, for example, if there is a plurality oftemperature-detecting parts for detecting the temperature of each of theareas S1 and S2 (one and two in the example of FIG. 4 for the sake ofconvenience), and an average value of these temperature detection valuesis set as detection results. As the control method, if it is judged, forexample, that the temperature of the center-section area S1 is higherthan the temperature of the outside area S2 at the time of heating theLCD substrate 10, the flow adjustment parts 63-1 and 63-2 are controlledso that a flow of the first heat exchange gas with respect to theoutside partition chamber 82 becomes large so as increase an amount ofheat given from the first heat exchange gas to the outside area S2 toattempt uniformization of the temperature. Additionally, if it isjudged, for example, that the temperature of the center-section area S1is lower than the temperature of the outside area S2 at the time ofcooling the LCD substrate 10, the flow adjustment parts 73-1 and 73-2are controlled so that a flow of the second heat exchange gas becomeslarge with respect to the outside partition chamber 82 so as to increasean amount of heat taken by the second heat exchange gas from the outsidearea to attempt uniformization of the temperature.

[0041] According to the present embodiment, the in-plane uniformity oftemperature when heating and cooling the LCD substrate can be furtherimproved. In the above-mentioned embodiment, the number of divided areasof the LCD substrate 10 is not limited to two pieces, and may be threeor more pieces. Additionally, it may be divided into left and rightinstead of dividing into the center area and the outside area.Furthermore, as for the control method, instead of adjusting a flow inaccordance with temperature detection results, two systems may beprepared so as to adjust the gas temperature with respect to thetemperature control part 62 or adjust both flow and temperature. Whencontrolling temperature, if the temperature of the outside area S2 islower than the center-section area S1 when cooling the LCD substrate 10for example, a control is performed so that the temperature of the gassupplied to the outside area S2 is set higher than the gas supplied tothe center-section area S1.

[0042]FIG. 6 is a diagram showing a third embodiment of the presentinvention. In this embodiment, an amount of heat exchange gas sufficientfor one time heat exchange is accumulated in each of the gas-supply pipe55 for the first heat exchange gas and the gas-supply pipe 56 for thesecond heat exchange gas. Moreover, for example, tanks 60 and 70equipped with a temperature control part and valves 65, 66, 75 and 76are provided. The capacity and internal pressure of the tanks 60 and 70and the supply flows of the first and second heat exchange gas is set inaccordance with a balance between an evacuation capacity of an exhaustpump which is connected to the exhaust pipe 46 and not illustrated, anda pressure inside the reaction container 4 at the time of start of heatexchange (start of heating or cooling).

[0043] In this example, when supplying the first heat exchange gas(second heat exchange gas) to the reaction container 4, after openingthe valves 64 and 66 (74, 76) and completing a heat exchange, a gas isaccumulated in the tank 60 (70) prior to a subsequent heat exchange.According to such an approach, since the a temperature control can beachieved by previously accumulating a gas in the tank, a temperaturecontrol can be performed simply and certainly by acquiring data byperforming experiments previously.

[0044] As mentioned above, according to the present invention, whenapplying a heat treatment to a glass substrate, a temperature can bechanged (heating and/or cooling) rapidly with high uniformity over anentire surface, thereby acquiring a high throughput.

[0045] The present invention is not limited to the specificallydisclosed embodiments, and variations and modifications may be madewithout departing from the scope of the present invention.

1. A heat treatment method of performing a heat treatment using a heattreatment apparatus constituted by connecting airtightly a carrierchamber which a substrate is carried in and carried out, a conveyancechamber for conveying the substrate and a hot-wall type heat treatmentunit for heat-treating the substrate, a glass substrate for liquidcrystal displays being taken from a substrate carrier in the carrierchamber by conveying means in said conveyance chamber and being conveyedinto said heat treatment unit in which a heat treatment is applied tothe glass substrate, the method comprising: a step of conveying theglass substrate from said conveyance chamber into a reaction containerinside said heat treatment unit; a step of heating an interior of saidreaction container at a process temperature so as to apply a heattreatment to the glass substrate; a step of supplying a gas for heatexchange to a surface of said glass substrate so as to perform heatexchange between said glass substrate and the gas in at least one of astep of raising a temperature inside said reaction container to theprocess temperature and a step of decreasing the temperature of thereaction container after the heat treatment; and a step of carrying theheat treated glass substrate out of said reaction container.
 2. The heattreatment method as claimed in claim 1, wherein said gas for heatexchange is blown from a gas supply part opposite to the surface of theglass substrate to substantially the entire surface of the glasssubstrate.
 3. The heat treatment method as claimed in claim 1, whereinsaid gas for heat exchange is previously adjusted to a predeterminedtemperature before being supplied to inside said reaction container. 4.The heat treatment method as claimed in claim 1, wherein a first gas forheat exchange is supplied to the glass substrate in a step of raisingthe temperature inside said reaction container to a process temperature,and a second gas for heat exchange, which has a temperature lower thanthe temperature of said first gas for heat exchange, is supplied to saidglass substrate in a step of decreasing the temperature inside saidreaction container after the heat treatment.
 5. The heat treatmentmethod as claimed in any one of claims 1 to 3, including a step ofsupplying a gas for heat exchange to a surface of said glass substratein the step of raising the temperature inside said reaction container tothe process temperature, and performing, during the step of supplying,at least one of increasing an amount of the gas for heat exchange andraising a temperature of the gas for heat exchange before being suppliedto said reaction container.
 6. The heat treatment method as claimed inany one of claims 1 to 3, including a step of supplying a gas for heatexchange to a surface of said glass substrate in the step of decreasingthe temperature inside said reaction container to the processtemperature, and performing, during the step of supplying, at least oneof increasing an amount of the gas for heat exchange and decreasing atemperature of the gas for heat exchange before being supplied to saidreaction container.
 7. The heat treatment method as claimed in any oneof claims 1 to 3, including: a step of dividing the glass substrateplaced in said reaction container into a plurality of areas andsupplying independently a gas for heat exchange to each of the areas; astep of detecting a temperature of each of the divided areas of saidglass substrate; and a step of controlling at least one of an amount offlow and a temperature of the gas for heat exchange to be supplied toeach divided area.
 8. A heat treatment apparatus constituted byconnecting airtightly a carrier chamber which a substrate is carried inand carried out, a conveyance chamber for conveying the substrate and ahot-wall type heat treatment unit for heat-treating the substrate, aglass substrate for liquid crystal displays being taken from a substratecarrier in the carrier chamber by conveying means in said conveyancechamber and being conveyed into said heat treatment unit in which a heattreatment is applied to the glass substrate, comprising: a placementpart for placing the glass substrate in said reaction container; a gassupply part for supplying a gas for heat exchange to a surface of theglass substrate placed on the placement part; a flow passage opening andclosing part provided to a gas flow path for delivering the gas to saidgas supply part; a control part controlling the flow passage opening andclosing part so as to supply a gas for heat exchange to said glasssubstrate in at least one of a step of raising a temperature inside saidreaction container to the process temperature and a step of decreasingthe temperature of the reaction container after the heat treatment. 9.The heat treatment apparatus as claimed in claim 8, wherein said gassupply part is provided so as to oppose to a surface of the glasssubstrate placed on said placement part, and the gas for heat exchangeis blown to substantially the entire surface of the glass substrate. 10.The heat treatment apparatus as claimed in claim 8, further comprising atemperature adjusting part for previously adjusting a temperature of thegas for heat exchange to a predetermined temperature before the gas forheat exchange is supplied to inside said reaction container.
 11. Theheat treatment apparatus as claimed in claim 8, wherein said gas supplypart supplies a first gas for heat exchange to the glass substrate in astep of raising the temperature inside said reaction container to aprocess temperature, and supplies a second gas for heat exchange, whichhas a temperature lower than the temperature of said first gas for heatexchange, to said glass substrate in a step of decreasing thetemperature inside said reaction container after the heat treatment. 12.The heat treatment apparatus as claimed in claims 8, wherein said gassupply part is configured and arranged to divide the glass substrateplaced in said reaction container into a plurality of areas and so as tosupply independently a gas for heat exchange to each of the dividedareas, and including: a temperature detecting part detecting atemperature of each of the divided areas of said glass substrate; andmeans for controlling at least one of an amount of flow and atemperature of the gas for heat exchange to be supplied to each dividedarea.
 13. The heat treatment apparatus as claimed in claims 8, wherein atank is provided on an upstream side of said flow passage opening andclosing part for accumulating an amount of the gas for heat exchangenecessary for one time heat exchange.